mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-10-22 05:59:31 +08:00
Chris Tate
e81e4f5ab5
- ambientUndefVarRootOf walks calls, `new`, optional chains, assertions, instantiation expressions, and tagged templates, and accepts `declare function` and trap-binding roots: Node erases the declaration, so the root read IS the crash — lowerCall, member reads, assignments, and variable declarations lower the whole statement to the catchable ReferenceError, arguments never evaluate, and the never-initialized binding registers as a trap whose references can never run
- never-read unmappable bindings with value-only initializers and writes emit nothing: Node builds the value and drops it, so `var xs2: typeof Array;` and the write-only `var f2: { <T, U>(x: T, y: U): T }` compile instead of fencing on a type the program never consumes
- null!/as-any bindings whose types keep generic signatures (or intern empty record shapes) register no storage; generic-method calls and member reads through them compile to Node's exact TypeError, nullish-to-nullish flows to nothing, heritage-clause uses decline the family so mixin resolution keeps its fence, and checked-dynamic (`any`) bindings keep their dyn story untouched
- assertion-shaped generic arrows (`< <T>(x: T) => T >((x) => x)`) register like annotated bindings and monomorphize per call; stdlib generic members (Promise.then, Object.defineProperty) take the SC2020 lib fence, and Function.prototype.apply/call/bind on compiled function values name the direct-call spelling
- diagnostics fixtures that used `declare` to conjure unconstructible values now conjure them by cast so each fence family keeps its pin; snapshots re-recorded, the deferred checker-panic diagnostic now flushes at its first reference as designed
46 lines
1.4 KiB
TypeScript
46 lines
1.4 KiB
TypeScript
// SC2009: supported shapes over a component type outside its slot — the
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// container is not the blocker, and each message names the component.
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// Map keys are limited to numbers and strings.
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const byFlag = new Map<boolean, string>();
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console.log(byFlag);
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// Map values have no slot for functions.
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const listeners = new Map<string, () => void>();
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console.log(listeners);
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// Set elements are limited to numbers and strings.
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const flags = new Set<boolean>();
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console.log(flags);
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// Arrays cannot hold Map elements yet.
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const rows: Map<string, number>[] = [];
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console.log(rows);
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// A Map arm has no home in a compiled union.
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function report(maybe: Map<string, number> | undefined): number {
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return maybe === undefined ? 0 : maybe.size;
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}
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console.log(report(undefined));
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// A rest parameter has no compiled calling convention.
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const sum = (...xs: number[]): number => xs.length;
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const storedSum = sum;
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console.log(storedSum(1, 2));
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// A function's return type carries the failure. The value arrives through
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// a cast, not an ambient declare (a declare-rooted chain would compile to
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// Node's ReferenceError at the root instead).
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const makeWeak = (0 as unknown) as () => WeakMap<object, number>;
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const storedMake = makeWeak;
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console.log(storedMake());
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// A record member's type carries the failure.
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interface Holder {
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label: string;
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cache: WeakMap<object, number>;
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}
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const held = (0 as unknown) as Holder;
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const kept = held;
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console.log(kept.label);
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